Copyright 2014 Google Inc. All Rights Reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

MetadataReadOnlyGoogleCloudStorage holds a collection of Storage object/bucket metadata entries
and serves listObjectNames, listObjectInfo, getItemInfos, and getItemInfo exclusively from the
in-memory cache. All other operations will throw an UnsupportedOperationException. For the time
being, such unsupported operations include bucket info list operations like listBucketInfo and
listBucketNames.
This instance will supplement fake GoogleCloudStorageItemInfos for pure implicit directories
if there is no metadata entry for the directory object itself. This means that some directory
objects will list info that is inconsistent with an actual listing.